<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head th:replace="main::head">
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div class="container-fluid d-flex flex-column ">
    <form class="row justify-content-center" action="/join-class">
        <div class="col-md-7">
            <label class="form-label">班级代码:</label>
            <input type="text" class="form-control mb-3" placeholder="" name="id">
            <button type="submit" class="btn btn-primary">加入</button>
        </div>
    </form>
</div>

</body>
</html>